The Compendium of Caraka 1.11.8

1.11.8

satāṃ ca rūpāṇāmatisannikarṣādativiprakarṣādāvaraṇāt karaṇadaubalyānamanonavasthānāt samānābhihārādabhibhavādatisaukṣmyācca pratyakṣānupalabdhiḥ; tasmādaparīkṣitametaducyate pratyakṣamevāsti, nānyadastīti //

And even of existent forms, non-perception through the senses occurs due to extreme proximity, extreme distance, obstruction, weakness of the sense organ, inattention of the mind, blending with similar things, suppression, and extreme minuteness. Therefore, it is unexamined when said: 'Only what is perceptible exists; nothing else exists.'